Hot spring and Firehole River, Yellowstone National Park

A hot spring along side of the Firehole River in Yellowstone National Park, Montana. Many hot springs from the geyser basins drain into the Firehole River, maintaining warmer temperatures in the winter that can be beneficial to trout, but that can be too warm in the summer. The warmer temperatures also influence the benthic invertebrates such as mud snails (Physa virgata) that have invaded the area. See: